Research On Optimal Lot Size And Control Strategy Of Mutil-Variety Mixed Production In Manufacturing Enterprises

Based on a detailed understanding about the research status and the major production schedule and control system, this thesis makes a deeply research on two aspects of multi-variety mixed production including optimal lot size and control strategy.Firstly, it points out some questions that have already existed in multi-variety mixed production, through comparative analyses the application scope, advantages and disadvantages of Manufacturing Recourse Planning, Just In Time, Theory Of Constraints and Manufacturing Execution System, providing theoretical support for further research.Then, using the relevant queue theory from Operation Research, derives the single variety optimal lot size based on the minimized production lead time, through analyzing the two extreme cases, hands out that single-piece flow can solve many problems of the enterprise business, thereupon proposes a production lead time calculation method for job-shop manufacture; because of the direct relationship between production lead time and shared process adjusted time, discusses the meaning of reducing the shared process adjusted time, also gives the specific methods; finally derives the optimal transfer lot size and production lead time calculation method when the device has the highest utilization.Finally, it introduces the theory of factory physics, gives the parameters calculation methods of best case, worst case and practice worst case; makes a detailed research on the influence of cycle time by changing productivity, then makes a conclusion that improving the non-bottleneck productivity can increase the production throughout, not like it is mentioned in the Theory Of Constraints that changing the non-bottleneck productivity do nothing to the production throughout; gives the definition of Push and Pull, Constant Work In Process Control Strategy(CONWIP), through comparative analyses CONWIP with Kanban Control Strategy and DBR Control Strategy, finding out that CONWIP is better than Kanban and DBR in many aspects, but is also not perfect, so puts forward a Mixed Control Strategy based on CONWIP combining Kanban and DBR, then introduces the key points of Mixed Control Strategy, and gives the calculation method of production lead time.